The hypergranular type of acute promyelocytic leukemia (APL) is characterized by heavy granulation and the presence of Auer rods. These granules are usually small, azurophilic, and have the appearance of the primary granules of normal promyelocytes. There have been several reports of myeloid leukemias, including APL, with the unusual finding of large granules (inclusions) simulating the inclusi...

The genetic and molecular bases of various types of congenital pigmentary disorders have been classified in the past 10 years, as follows: (1) disorders of melanoblast migration in the embryo from the neural crest to the skin: piebaldism; Waardenburg syndrome 1-4 (WS1-WS4); dyschromatosis symmetrica hereditaria. (2) Disorders of melanosome formation in the melanocyte: Hermansky-Pudlak syndrome ...

Platelets from two probands homozygous for the Chediak-Higashi syndrome have approximately 10% of the normal number of serotonin-containing dense bodies as visualized electron microscopically in air-dried whole mounts. Since transport of serotonin across the platelet plasma membrane proceeds at a normal rate, and the few dense bodies present appear to store normal amounts of serotonin, the abse...